ABSTRACT
Purpose: The purpose of this study was to highlight the clinical and molecular features of 13 Raoultella ornithinolytica strains isolated from clinical environments in Ecuador, and to perform comparative genomics with previously published genomes of Raoultella spp. As Raoultella is primarily found in environmental, clinical settings, we focused our work on identifying mechanisms of resistance that can provide this bacterium an advantage to establish and persist in hospital environments. Methods: We analyzed 13 strains of Raoultella ornithinolytica isolated from patients with healthcare associated infections (HAI) in three hospitals in Quito and one in Santo Domingo de Los Tsáchilas, Ecuador, between November 2017 and April 2018. These isolates were subjected to phenotypic antimicrobial susceptibility testing, end-point polymerase chain reaction (PCR) to detect the presence of carbapenemases and whole-genome sequencing. Results: Polymerase chain reaction revealed that seven isolates were positive isolates for blaOXA-48 and one for blaKPC-2 gene. Of the seven strains that presented the blaOXA-48 gene, six harbored it on an IncFII plasmid, one was inserted into the bacterial chromosome. The blaKPC gene was detected in an IncM2/IncR plasmid. From the bioinformatics analysis, nine genomes had the gene blaOXA-48, originating from Ecuador. Moreover, all R. ornithinolytica strains contained the ORN-1 gene, which confers resistance for ß-lactams, such as penicillins and cephalosporins. Comparative genome analysis of the strains showed that the pangenome of R. ornithinolytica is considered an open pangenome, with 27.77% of core genes, which could be explained by the fact that the antibiotic resistance genes in the ancestral reconstruction are relatively new, suggesting that this genome is constantly incorporating new genes. Conclusion: These results reveal the genome plasticity of R. ornithinolytica, particularly in acquiring antibiotic-resistance genes. The genomic surveillance and infectious control of these uncommon species are important since they may contribute to the burden of antimicrobial resistance and human health.
ABSTRACT
Abstract Listeria monocytogenes is one of the most important bacteria associated with food-borne diseases, soft cheese being an important L. monocytogenes vehicle. In Ecuador, softcheese is consumed in 84.3% of urban households. We determined the prevalence of L. mono-cytogenes and serogroups in 260 fresh artisanal soft cheese samples collected in 18 of 24Ecuadorian provinces. Listeria spp. detection was carried out by culture-dependent and inde-pendent methods; 14.23% of samples were positive for L. monocytogenes. Serogroup IVb wasfound in 83.78% of the food isolates. Serogroups IIb and IIa were present in 8.11% of our isolates.To our knowledge, this is the first report of L. monocytogenes serogroups associated with foodin Ecuador; we also found serogroup similarities between cheese isolates and clinical isolates.
Resumen Listeria monocytogenes es una de las bacterias más importantes asociadas conenfermedades transmitidas por alimentos, y el queso fresco es un importante vehículo de trans-misión de L. monocytogenes. En Ecuador, el consumo de quesos frescos se produce en el 84,3%de los hogares urbanos. Determinamos la prevalencia de L. monocytogenes y sus serogrupos en260 muestras de queso fresco artesanal recolectadas en 18 de las 24 provincias ecuatorianas.La detección de Listeria spp. se llevó a cabo mediante métodos independientes y dependientesde cultivo; el 14,23% de las muestras fueron positivas para L. monocytogenes.
ABSTRACT
Listeria monocytogenes is one of the most important bacteria associated with foodborne diseases, soft cheese being an important L. monocytogenes vehicle. In Ecuador, soft cheese is consumed in 84.3% of urban households. We determined the prevalence of L. monocytogenes and serogroups in 260 fresh artisanal soft cheese samples collected in 18 of 24 Ecuadorian provinces. Listeria spp. detection was carried out by culture-dependent and independent methods; 14.23% of samples were positive for L. monocytogenes. Serogroup IVb was found in 83.78% of the food isolates. Serogroups IIb and IIa were present in 8.11% of our isolates. To our knowledge, this is the first report of L. monocytogenes serogroups associated with food in Ecuador; we also found serogroup similarities between cheese isolates and clinical isolates.
